Description

The measurement of the temperature of window glass exposed to direct solar radiation was studied experimentally under clear sky conditions. Thermocouples of different constructions were mounted on the surface of a 3.18 mm (i/8-inch) window glass panel and their outputs were monitored simultaneously under both direct solar radiation and shaded conditions. The thermocouples used for the experiment were a pair of thin foil type with butt-bonded bare metal junction, a pair of thin foil type encased in thin polymer/glass laminates, and a 40 gauge wire, beaded junction. For the foil types, one from each pair was coated with a highly reflective white paint. Shading was applied after stable output was established, and responses from the step change in irradiation level were recorded. It was found that there can be a 0.2°C to 0.7°C difference in the measured temperature for the glass surface between a bare metal junction and a junction coated with a high reflectivity (in the shortwave spectrum) paint. The difference in indicated temperature between an unpainted laminated junction and a painted junction can be as high as 1.0°C. The radiative properties of the junction’s surface, both in the solar and the infrared spectrum, are shown to have equal effect on the surface temperature measurement.

Units: SI

Citation: Symposium, ASHRAE Transactions, 1988, vol. 94, pt. 2, Ottawa

Product Details

Published:

1988

Number of Pages:

10

File Size:

1 file , 840 KB

Product Code(s):

D-OT-88-07-5